Chapter 2- Structure And Function Of Cells Flashcards

0
Q

Motor neuron

A

Located within the CNS that controls the contraction of a muscle or the secretion of a gland

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1
Q

Sensory neuron

A

Detects changes in the environment and send information about these changes to CNS

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2
Q

Interneuron

A

A neuron located entirely within the CNS

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3
Q

Central nervous system (CNS)

A

Brain and spinal cord

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4
Q

Peripheral nervous system (PNS)

A

Nerves

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5
Q

Soma

A

Cell body of a neuron which contains the nucleus

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6
Q

Dendrite

A

A branched, treelike structure attached to the soma of a neuron, received information from the terminal buttons of other neurons

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7
Q

Synapse

A

A junction between the terminal button of an axon and the membrane of another neuron

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8
Q

Axon

A

The long, cylindrical structure that conveys information from the soma of a neuron to its terminal buttons

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9
Q

Multipolar neuron

A

A neuron with one axon and many dendrites attached to its soma

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10
Q

Bipolar neuron

A

A neuron with one axon and one dendrite attached to its soma

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11
Q

Unipolar neuron

A

A neuron with one axon attached to its soma, the axon divides, with one branch receiving sensory information and the other sending info to CNS

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12
Q

Terminal button

A

The bud at the end of a branch of an axon, forms synapses with another neuron, sends information to that neuron

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13
Q

Neurotransmitter

A

A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron

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14
Q

Membrane

A

Boundary of the cell; consists of a double layer of lipid molecules

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15
Q

Nucleus

A

A structure in the central region of a cell; contains nucleolus and chromosomes

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16
Q

Nucleolus

A

A structure within the nucleus that produces ribosomes

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17
Q

Ribosome

A

A cytoplasmic structure, made of protein, that serves as the site of production of proteins translated from mRNA

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18
Q

Messenger ribonucleic acid (mRNA)

A

A macromolecule that delivers genetic information concerning the synthesis of a protein from a portion of a chromosome to a ribosome

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19
Q

Enzyme

A

A molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts.

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20
Q

Mitochondrion

A

An organelle that is responsible for extracting energy from nutrients

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21
Q

Golgi apparatus

A

A complex of parallel membranes in the cytoplasm that wraps the products of the secretory cell

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22
Q

Exocystosis

A

The secretion of a substance by a cell through means of vesicles; the process by which neurotransmitters are secreted

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23
Q

Lysosomes

A

Organelles surrounded by membrane; contains enzymes that break down waste products

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24
Q

Microtubule

A

A long strand of protein filaments arranged around a hollow core; involved in transporting substances from place to place within the cell

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25
Q

Axoplasmic transport

A

An active process by which substances are propelled along mixrotubules that run the length of the axon

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26
Q

Anterograde

A

In a direction along an axon from the cell body toward terminal buttons

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27
Q

Retrograde

A

In a direction along an axon from the terminal buttons toward cell body

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28
Q

Glia

A

The supporting cells of the central nervous system (astrocytes, oligodendrocytes, microglia)

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29
Q

Astrocytes

A

Glial cell- provides nutrients and other substances and regulates the chemical composition of the extracellular fluid

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30
Q

Phagocytosis

A

The process by which cells engulf and digest other cells or debris caused by cellular degeneration

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31
Q

Oligodendrocyte

A

Glial cell that forms myelin sheaths

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32
Q

Myelin sheath

A

A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons

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33
Q

Node of ranvier

A

A naked portion of a myelinated axon between adjacent oligodendroglia or Schwann cells

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34
Q

Microglia

A

Smallest of glial cells; act as phagocytes and protect the brain from invading microorganisms

35
Q

Schwann cell

A

A cell in the peripheral nervous system that is wrapped around a myelinated axon

36
Q

Blood-brain barrier

A

A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brains capillaries

37
Q

Electrode

A

A conductive medium that can be used to apply stimulation or to record electrical potentials

38
Q

Membrane potential

A

The electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell

39
Q

Resting potential

A

The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials (-70 mV in giant squid axon)

40
Q

Depolarization

A

Reduction (toward zero) of the membrane potential of a cell from its normal resting potential

41
Q

Hyperpolarization

A

An increase in the membrane potential of a cell, relative to the normal resting potential

42
Q

Action potential

A

The brief electrical impulse that provides the basis for conduction of information along an axon

43
Q

Threshold of excitation

A

The value of the membrane potential that must be reached to produce action potential

44
Q

Diffusion

A

Movement of molecules from regions of high concentration to regions of low concentration

45
Q

Electrolyte

A

An aqueous solution of a material that ionizes-namely, A soluble acid, base, or salt

46
Q

Ion

A

A charged molecule. Cations are positively charged. Anions are negatively charged

47
Q

Electro static pressure

A

The attractive force between atomic particles charged with opposite signs or the repulsive force between atomic particles charged with the same sign

48
Q

Sodium-potassium transporter

A

A protein found in the membrane of all cells that extrude sodium ions from and transports potassium ions into the cell

49
Q

Ion channel

A

A specialized protein molecule that permits specific ions to enter or leave cells

50
Q

Voltage-dependent ion channel

A

An ion channel that opens or closes according to the value of the membrane potential

51
Q

All or none law

A

The principle that once an action potential is triggered in an axon, it is propagated, without decrement, to the end of the fiber

52
Q

Rate law

A

The principle that variations in the intensity of the stimulus or other information being transmitted in an axon are represented by variations in the rate at which that acts on fires

53
Q

Saltatory conduction

A

Conduction of action potentials by myelinated axon. The action potential appears to jump from one node of ranvier to the next

54
Q

Postsynaptic potential

A

Alterations in the membrane potential of a postsynaptic neuron, produced by liberation of neurotransmitters at the synapse

55
Q

Binding site

A

The location on a receptor proteins to which a ligand binds

56
Q

Ligand

A

A chemical that binds with the binding site of a receptor

57
Q

Dendritic spine

A

A small bud on the surface of a dendrite, with which a terminal button of another neuron form a synapse

58
Q

Presynaptic membrane

A

The membrane of a terminal button that lives adjacent to the postsynaptic membrane and through which the neurotransmitter is released

59
Q

Postsynaptic membrane

A

The cell membrane opposite the terminal button and a synapse; The membrane of the cell that receives the message

60
Q

Synaptic cleft

A

The space between the presynaptic membrane in the postsynaptic membrane

61
Q

Synaptic vesicles

A

A small, hollow, bead like structure found in the terminal buttons; contains molecules of a neurotransmitter

62
Q

Postsynaptic receptor

A

A receptor molecule in the postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter

63
Q

Neurotransmitter-dependent ion channel

A

An ion channel that opens when a molecule of a neurotransmitter binds with the postsynaptic receptor

64
Q

Ionotropic receptor

A

A receptor that contains a binding site for the neurotransmitter and an ion channel that opens when a molecule of the neurotransmitter attaches to the binding site

65
Q

Metabotropic receptor

A

A receptor that contains a binding site for a neurotransmitter; activates an enzyme that begins a series of events that opens an ion channel elsewhere in the membrane of the cell when I molecule of the neurotransmitter attaches to the binding site

66
Q

G protein

A

A protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activate the receptor

67
Q

Second Messenger

A

A chemical produced when a G protein activate; carries a signal that results in the opening of the ion channel or causes other events to occur in the cell

68
Q

Excitatory postsynaptic potential (EPSP)

A

And excitatory depolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button

69
Q

Inhibitory postsynaptic potential (IPSP)

A

And inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button

70
Q

Reuptake

A

The reentry of a neurotransmitter just liberated by a terminal button back and through its membrane, thus terminating the postsynaptic potential

71
Q

Enzymatic deactivation

A

The destruction of a neurotransmitter by an enzyme after it’s release-for example, the destruction of acetylcholine by acetylcholinesterase

72
Q

Acetylcholine

A

Neurotransmitter found in the brain, spinal cord, and part of the peripheral nervous system; responsible for muscular contraction

73
Q

Acetylcholinesterase

A

The enzyme that destroys acetylcholine soon after it is liberated by the terminal buttons, terminating the postsynaptic potential

74
Q

Neural integration

A

The process by which inhibitory and excitatory postsynaptic potential summate and control the rate of firing of a neuron

75
Q

Auto receptor

A

Receptor molecule located on a neuron that response to the neurotransmitter released by that neuron

76
Q

Presynaptic inhibition

A

The action of a presynaptic terminal button and axoaxonic synapse; reduces the amount of neurotransmitter released by the post synaptic terminal button

77
Q

Presynaptic facilitation

A

The action of the presynaptic terminal button in an axoaxonic synapse; increases the amount of neurotransmitter release by the post synaptic terminal button

78
Q

Gap junction

A

A special junction between cells that permits direct communication by means of electrical coupling

79
Q

Neuromodulator

A

A naturally secreted substances act like a neurotransmitter except that it is not restricted to the synaptic cleft but diffuses through the extracellular fluid

80
Q

Peptide

A

A chain of amino acids joined together by peptide bonds. Most neuromodulators, and some hormones consist of peptide molecules

81
Q

Hormone

A

A chemical substance that is released by an endocrine gland that has effects on target cells in other organs

82
Q

Endocrine gland

A

A gland that liberates it secretions into the extracellular fluid around capillaries and hence into the bloodstream

83
Q

Target cell

A

The type of cell that is directly affected by a hormone or other chemical signal

84
Q

Steroid

A

A chemical of low molecular weight, derived from cholesterol. Steroid hormones affect their target cells by attaching two receptors found within the nucleus